<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>打印金字塔</title>
	</head>
	<body>
		<script>
			var num=prompt("请输入行数");
			for (var i=1;i<=num;i++) {
				for (var k=1;k<=num-i;k++) {
					document.write("&nbsp;");
				}
				for (var j=1;j<=2*i-1;j++) {
					document.write("*");
				}
				document.write("</br>");
			}
		</script>
	</body>
</html>
